Apparatus for texturizing filaments



10, 1963 E. A. TAYLOR, JR

APPARATUS FOR ,TEX'I'URIZING FILAMENTS Filed Dec. 12. 1960 INVENTOR. ERNEST A.TAYLOR,JR. BY 3 f a FIG'.3.

ATTORNEY United States Patent 3,113,366 APPARATUS FUR TEXTURIZIN G FELAMENTS Ernest A. Taylor, in, Decatur, Ala, assignor, by mesne assignments, to Monsanto @hemical Qompa'ny, a corporation of Delaware Filed Dec. 12, 196i), Ser. No. 75,238 Claims. (Cl. 23-4) This invention relates to apparatus for texturizing filaments and more particularly to apparatus for differentially texturizing thermoplastic filaments.

it is a well known fact that it is necessary to texturize or crimp man-made fibers which are to be cut into staple. The reason for this is that it is necessary to provide some fiber characteristic which Will resist longitudinal movement of one fiber relative to another. Without this characteristic the staple fibers would slide too easily along each other in the assembled yarn, thereby resulting in a yarn of very little tensile strength. Natural fibers such as wool have an inherent curl or roughness which provides a good frictional engagement between adjacent fibers. However, man-made fibers which are inherently straight and smooth, must be treated in some way to impart good frictional characteristics. It is also necessary to treat eontinuousfilament, man-made fibers to give them better covering characteristics, greater stretchahility, more elasticity, a better hand, or other specific qualities as required depending upon their end application.

One method of so treating man-made fibers is to texturize or crimp the fibers. The crimping is usually accomplished by passing a heated tow of filaments between a pair of gears, the teeth of the gears imparting a Wavy configuration to the thermoplastic filaments. This arrangement has several disadvantages. On of these disadvantages is that, due to the physical limitations on gear teeth sizes, it is not possible to obtain a crimp of very small size. The same is true where smooth crimping rolls are used. Another disadvantage is that a particular pair of crimping gears cannot be used to obtain a crimp of various sizes. By crimp size, we mean generally the amplitude and length of the wavy configuration imparted to the filaments by the crimping operation.

A further disadvantage of conventional gear crimping operations is that these operations cannot produce a tow in which the filaments are completely looped, i.e., where the slack filament configuration defines a series of loops rather than a wave configuration.

Other types of crimping or texturizlng operations in- Volve pulling the yarn across a knife edge or twisting the yarn and then heat setting it. The disadvantage of these types of texturizing operations is that the apparatus has limited life or is not conducive to high speed operation. ln crimping operations where rolls feed the yarn into a hot stuffing box the high heat duration is likely to result in poor dye uniformity.

With these problems in mind, one of the objects of this invention is to provide a novel and improved yarn texturizing apparatus.

Another object of this invention is to provide an apparatus for annealing one side of a filament without changing the other side.

A further object of this invention is to provide an apparat'us having a nozzle for directing a heated gas onto a yarn carried by a relatively cool roll.

Still another object of this invention is to provide an apparatus having a novel nozzle which directs a stream of heated gas onto and along a moving yarn without disrupting the relationship of the filaments .in the yarn.

One embodiment of the invention contemplates a non zle for directing a stream of heated gas onto a yarn carried by a relatively cool roll. The nozzle, which is positioned Very close to the roll, is provided W1 1 an opening which is rectangular in configuration, the long axis of the opening being positioned transversely to the path of travel of the yarn.

T he heated gas leaves the nozzle and heats the exposed side of the filaments in the yarn to a temperature sufficient to anneal or stress relieve the exposed sides. The opposite sides of the filaments are in contact with the relative cool roll and are thereby not affected by the hot gas, the roll serving as a heat-sink to prevent a substantial temperature rise in these opposite sides. When tension is removed from the yarn it draws up into a series of tight curls or coils. This gives the yarn great but iness. The method of so texturizing yarn is disclosed and claimed in copending application Serial No. 75,299, filed Decemher 12, 1960, in the name of Ernest A. Taylor, it. for Methods of Texturizing Filaments.

Other objects and advantages of the invention will come apparent when the following deta'ded description is read in conjunction with the drawing, in which:

FIGURE 1 is a front view of a yarn annealing apparatus showing the positioning of the air nozzle adjacent to a roll over which the yarn is advanced;

FIGURE 2 is an enlarged fragmentary view showing in greater detail the construction of the nozzle; and

FlGURE 3 is an end view of the nozzle showing the flow paths of the gas leaving the nozzle.

Referring now in detail to the drawing, a yarn ll is drawn from a package 12 and moved past a conventional tensioning device 14 to a driven heat-sink roll 7. The yarn ll takes a turn around the roll 17 and then advances to a takeup roll 13 which is driven in a well known manner.

A nozzle 2-1 positioned adjacent to the roll 17 directs a stream of heated gas from a source 22 onto the yarn 11. The nozzle 21 is positioned very close to the yarn ll so that the exposed sides of the individual filaments in the yarn are heated to or near the softening or melting point of the thermoplastic material so that those exposed sides are relieved of inherent stress. Since the yarn ll is under tension on the roll 17, it will be fiattencd and spread so that the individual filaments are both exposed to the heated gas and in contact with the roll 17. The occasional loss of contact of a filament with the roll, due to crossed filaments, does not apparently detract from the overall bulking effect.

The nozzle (FIGS. 2 and 3) may be made of stainless steel and is provided with a rectangular opening or orifice 23 through which heated air or other gas is directed onto the yarn. The nozzle is positioned so that the long axis of the rectangular opening is transverse or perpendicular to the path of travel of the yarn. A typical nozzle may have an outside diameter of A inch, a rectangular opening 0.015" X 0.125, and be spaced 0.003 from the surface of the heat-sink or heat-absorbing roll 17.

FIGURE 3 shows the flow pattern of heated air leaving the opening or orifice 23 and passing between the end of the nozzle and the roll 17. From this it. can be seen that the major portion of the heated air flows in a direction parallel to the yarn path. The flow pattern is determined both by the clearance between the end of the orifice and the periphery of the roll and the shape and position of the exit orifice. This flow pattern does not disturb the positioning of the individual filaments of the yarn as a transverse air current would.

The reason for this unexpected air flow pattern is not fully understood, but it is believed that at points B (FIG. 3) the air leaving the orifice expands so that its velocity drops and back pressure builds up, while at points A the air flows in parallel paths, thereby maintaining a high velocity. It is known that Where air velocity is highest,

al air pressure is lowest, so that it appears that the air streams A are in a low pressure area which tends to keep them from spreading out. It has been demonstrated that, at points C, ambient air is actually flowing toward the orifice 23, while, beyond points A, well defined streams of air are flowing away from the orifice.

The roll 17 is cooled by a stream of air from a nozzle 2s which is connected to an air source 27. This cools the roll 17 so that it serves as a heat sink or heat absorber to keep one side of each of the individual filaments of the yarn l1 relatively cool as the other side is heated.

Factors which afiect the yarn bulking or texturizing operations are gas temperature, spacing of the nozzle from the heat-sink roll, gas supply temperature, yarn speed, yarn tension, heat-sink roll temperature and temperature of the yarn prior to contact with the roll. The amount of heat that must be applied to the exposed side of the fiber will vary in accordance With the softening or melting point of the fiber. Thus, a fiber having a relatively low melting point will not require as much heat for bulking as will a high melting point fiber. Since it is very difiicult to actually determine the yarn temperature, the process is best carried out by controlling the gas pressure and temperature to give the desired result on the particular yarn being treated. Since one side of each filament is in contact with the relatively cool roll, more heat is required than would be the case if the roll were not present to absorb heat.

In operation of this apparatus, the yarn 11 is advanced from the yarn package 12 over the heat-sink roll 17 to the takeup roll 18. As the yarn passes the nozzle 21 the stream of hot air leaving the nozzle heats the exposed side of the yarn to a temperature high enough to stress relieve this exposed side. The roll 17, being cooled by the cold air from the nozzle 26, acts as a heat sink or heat absorber to prevent a substantial temperature rise in the side of the yarn in contact with the roll. This side of the yarn, because of the heat-absorbing characteristics of the roll 17, does not reach the stress relief temperature. Thus, one side of the yarn is annealed or stress-relieved while the other is not.

The fact that one side of the filament is heated to near or above its softening point while the other side is cooled results in a texturizing or bulking of the yarn, the degree or amount of texturizing being dependent upon the yarn temperature differential under a given yarn tension. The relatively cool roll 17 in contact with the yarn filaments serves as a heat sink to prevent an undesired temperature rise in one side of the filament. Thus, one side of each filament is cool relative to the other side.

The yarn can be preheated above its ambient temperature but not to its softening point, before passing on to the cool roll. This has the efiect of increasing the core temperature of each filament, enabling the annealing efiect of the heated gas to penetrate more deeply into the core of the yarn.

The fact that heat for annealing is applied to the yarn at one point, rather than along a length of the yarn, insures a superior result. This is because one side of the filament is heated to a high degree while the other side is kept relatively cool. If the yarn is heated along a length it is likely that, because of a twisting of the yarn under tension, portions of the yarn will be heated to equal degrees on both sidesresulting in no texturizing. It is well known that a yarn under tension may twist or turn slightly as it is advanced. If this twist occurs in the span or length of yarn which is being heated (as where the yarn passes over a heated moving belt), it may well result that both sides of the filament are heated to equal temperaturesone side being heated before the twist and the other side after the twist. By heating the yarn at a single point, this disadvantage is overcome.

It is to be understood that the process disclosed herein may be modified or that other embodiments may be conl templated without departing from the spirit and scope of the invention.

What is claimed is:

1. An apparatus for treating a filament, comprising a heat-absorbing element, means for advancing the filament over the heat-absorbing element, a supply of heated gas, and means connected to the gas supply for applying a stream of heated gas to the filament as said filament passes over said heat-absorbing element.

2. An apparatus for treating a filament, comprising a roll, means for advancing the filament over the roll, means for cooling the roll, a supply of heated gas, and means connected to the gas supply for applying a stream of heated gas onto the filament as said filament passes over said roll.

3. An apparatus for texturizing a yarn, comprising a roll, means for advancing the yarn over the roll, a supply of heated gas, a nozzle positioned adjacent to the roll and connected to the gas supply for directing a stream of hot air onto the yarn on said roll, and means for cooling the roll.

4. An apparatus for texturizing a yarn, comprising a roll, means for advancing the yarn over the roll, a supply of heated gas, a nozzle positioned adjacent to the roll and connected to the gas supply for directing a stream of heated air onto the yarn at a point on the roll, and a second nozzle positioned adjacent to the roll for directing a stream of cooling air onto the roll.

5. An apparatus for texturizing a yarn, comprising a heat-absorbing roll, means for advancing a yarn over the roll, a supply of heated gas, and a nozzle positioned adjacent to the roll and connected to the gas supply for directing a stream of heated gas onto the yarn on the roll, said nozzle having therein a rectangular opening the long axis of which is positioned normal to the path of travel of the yarn.

6. An apparatus for texturizing a yarn comprising a roll, means for advancing the yarn over the roll, a source of heated gas, a first nozzle connected to said gas source and positioned adjacent to the roll for directing a stream of heater gas onto the yarn passing over the roll, a source of cooling gas, and a second nozzle connected to the source of cooling gas and positioned adjacent to the roll for cooling said roll.

7. An apparatus for texturizing a yarn, comprising a roll, a source of heated gas, a first nozzle connected to said gas source and positioned adjacent to one side of the roll for directing a stream of heated gas onto the yarn passing over the roll, a source of cooling gas, and a second nozzle connected to the source of cooling gas and positioned adjacent to the opposite side of the roll for directing a stream of cooling gas onto said roll.

8. An apparatus for treating a filament, comprising a heat-absorbing roll, means for advancing a filament over the roll, a source of heated gas, a first nozzle having an opening positioned for directing a stream of gas onto one side of the filament passing over the roll, said nozzle being connected to said heated gas supply, said opening having a substantially rectangular configuration, a source of cooling gas, and a second nozzle connected to the source of cooling gas and positioned to direct a stream of said cooling gas onto said roll.

9. An apparatus for treating a filament, comprising a heat-absorbing element, means for advancing a filament across the heat-absorbing element, a source of heated gas, and means connected to the gas source for directing a stream of said heated gas onto the filament on the element, said stream having an elongated cross-sectional configuration, the longer axis of said configuration extending transversely across the filament.

10. An apparatus for treating a filament, comprising a heat-absorbing element, means for advancing a filament across the heat-absorbing element, a supply of heated gas, and means connected to the gas supply for applying a stream of said heated gas to said filament on said heat- 5 6 absorbing element, said stream being applied to the fila- 2,541,149 Birkenhauer Feb. 13, 1951 ment at substantially a point location thereon. 2,602,964 Sission July 15, 1952 2,974,391 Speakman et al Mar. 14, 1961 References Cited in the file of this patent 3,041,706 Brornley et a1 July 3, 1962 UNITED STATES PATENTS 5 FOREIGN PATENTS 2 40 22 Swank Apr. 20 1943 809,273 Great Britain Feb. 18, 1959 

1. AN APPARATUS FOR TREATING A FILAMENT, COMPRISING A HEAT-ABSORBING ELEMENT, MEANS FOR ADVANCING THE FILAMENT OVER THE HEAT-ABSORBING ELEMENT, A SUPPLY OF HEATED GAS, AND MEANS CONNECTED TO THE GAS SUPPLY FOR APPLYING A STREAM OF HEATED GAS TO THE FILAMENT AS SAID FILAMENT PASSES OVER SAID HEAT-ABSORBING ELEMENT. 